<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Db
 * @subpackage Adapter
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Pgsql.php 19051 2009-11-19 18:27:53Z mikaelkael $
 */


/**
 * @see Zend_Db_Adapter_Pdo_Abstract
 */
require_once 'Zend/Db/Adapter/Pdo/Abstract.php';


/**
 * Class for connecting to PostgreSQL databases and performing common operations.
 *
 * @category   Zend
 * @package    Zend_Db
 * @subpackage Adapter
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Db_Adapter_Pdo_Pgsql extends Zend_Db_Adapter_Pdo_Abstract
{

	/**
	 * PDO type.
	 *
	 * @var string
	 */
	protected $_pdoType = 'pgsql';

	/**
	 * Keys are UPPERCASE SQL datatypes or the constants
	 * Zend_Db::INT_TYPE, Zend_Db::BIGINT_TYPE, or Zend_Db::FLOAT_TYPE.
	 *
	 * Values are:
	 * 0 = 32-bit integer
	 * 1 = 64-bit integer
	 * 2 = float or decimal
	 *
	 * @var array Associative array of datatypes to values 0, 1, or 2.
	 */
	protected $_numericDataTypes = array(
	Zend_Db::INT_TYPE    => Zend_Db::INT_TYPE,
	Zend_Db::BIGINT_TYPE => Zend_Db::BIGINT_TYPE,
	Zend_Db::FLOAT_TYPE  => Zend_Db::FLOAT_TYPE,
        'INTEGER'            => Zend_Db::INT_TYPE,
        'SERIAL'             => Zend_Db::INT_TYPE,
        'SMALLINT'           => Zend_Db::INT_TYPE,
        'BIGINT'             => Zend_Db::BIGINT_TYPE,
        'BIGSERIAL'          => Zend_Db::BIGINT_TYPE,
        'DECIMAL'            => Zend_Db::FLOAT_TYPE,
        'DOUBLE PRECISION'   => Zend_Db::FLOAT_TYPE,
        'NUMERIC'            => Zend_Db::FLOAT_TYPE,
        'REAL'               => Zend_Db::FLOAT_TYPE
	);

	/**
	 * Creates a PDO object and connects to the database.
	 *
	 * @return void
	 * @throws Zend_Db_Adapter_Exception
	 */
	protected function _connect()
	{
		if ($this->_connection) {
			return;
		}

		parent::_connect();

		if (!empty($this->_config['charset'])) {
			$sql = "SET NAMES '" . $this->_config['charset'] . "'";
			$this->_connection->exec($sql);
		}
	}

	/**
	 * Returns a list of the tables in the database.
	 *
	 * @return array
	 */
	public function listTables()
	{
		$sql = "SELECT c.relname  AS table_name "
		. "FROM pg_catalog.pg_class c "
		. "JOIN pg_catalog.pg_roles r ON r.oid = c.relowner "
		. "LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace "
		. "WHERE n.nspname <> 'pg_catalog' "
		. "AND n.nspname !~ '^pg_toast' "
		. "AND pg_catalog.pg_table_is_visible(c.oid) "
		. "AND c.relkind = 'r' ";

		return $this->fetchCol($sql);
	}

	/**
	 * Returns the column descriptions for a table.
	 *
	 * The return value is an associative array keyed by the column name,
	 * as returned by the RDBMS.
	 *
	 * The value of each array element is an associative array
	 * with the following keys:
	 *
	 * SCHEMA_NAME      => string; name of database or schema
	 * TABLE_NAME       => string;
	 * COLUMN_NAME      => string; column name
	 * COLUMN_POSITION  => number; ordinal position of column in table
	 * DATA_TYPE        => string; SQL datatype name of column
	 * DEFAULT          => string; default expression of column, null if none
	 * NULLABLE         => boolean; true if column can have nulls
	 * LENGTH           => number; length of CHAR/VARCHAR
	 * SCALE            => number; scale of NUMERIC/DECIMAL
	 * PRECISION        => number; precision of NUMERIC/DECIMAL
	 * UNSIGNED         => boolean; unsigned property of an integer type
	 * PRIMARY          => boolean; true if column is part of the primary key
	 * PRIMARY_POSITION => integer; position of column in primary key
	 * IDENTITY         => integer; true if column is auto-generated with unique values
	 *
	 * @todo Discover integer unsigned property.
	 *
	 * @param  string $tableName
	 * @param  string $schemaName OPTIONAL
	 * @return array
	 */
	public function describeTable($tableName, $schemaName = null)
	{
		$sql = "SELECT
                a.attnum,
                n.nspname,
                c.relname,
                a.attname AS colname,
                t.typname AS type,
                a.atttypmod,
                FORMAT_TYPE(a.atttypid, a.atttypmod) AS complete_type,
                d.adsrc AS default_value,
                a.attnotnull AS notnull,
                a.attlen AS length,
                co.contype,
                ARRAY_TO_STRING(co.conkey, ',') AS conkey
            FROM pg_attribute AS a
                JOIN pg_class AS c ON a.attrelid = c.oid
                JOIN pg_namespace AS n ON c.relnamespace = n.oid
                JOIN pg_type AS t ON a.atttypid = t.oid
                LEFT OUTER JOIN pg_constraint AS co ON (co.conrelid = c.oid
                    AND a.attnum = ANY(co.conkey) AND co.contype = 'p')
                LEFT OUTER JOIN pg_attrdef AS d ON d.adrelid = c.oid AND d.adnum = a.attnum
            WHERE a.attnum > 0 AND c.relname = ".$this->quote($tableName);
		if ($schemaName) {
			$sql .= " AND n.nspname = ".$this->quote($schemaName);
		}
		$sql .= ' ORDER BY a.attnum';

		$stmt = $this->query($sql);

		// Use FETCH_NUM so we are not dependent on the CASE attribute of the PDO connection
		$result = $stmt->fetchAll(Zend_Db::FETCH_NUM);

		$attnum        = 0;
		$nspname       = 1;
		$relname       = 2;
		$colname       = 3;
		$type          = 4;
		$atttypemod    = 5;
		$complete_type = 6;
		$default_value = 7;
		$notnull       = 8;
		$length        = 9;
		$contype       = 10;
		$conkey        = 11;

		$desc = array();
		foreach ($result as $key => $row) {
			$defaultValue = $row[$default_value];
			if ($row[$type] == 'varchar') {
				if (preg_match('/character varying(?:\((\d+)\))?/', $row[$complete_type], $matches)) {
					if (isset($matches[1])) {
						$row[$length] = $matches[1];
					} else {
						$row[$length] = null; // unlimited
					}
				}
				if (preg_match("/^'(.*?)'::character varying$/", $defaultValue, $matches)) {
					$defaultValue = $matches[1];
				}
			}
			list($primary, $primaryPosition, $identity) = array(false, null, false);
			if ($row[$contype] == 'p') {
				$primary = true;
				$primaryPosition = array_search($row[$attnum], explode(',', $row[$conkey])) + 1;
				$identity = (bool) (preg_match('/^nextval/', $row[$default_value]));
			}
			$desc[$this->foldCase($row[$colname])] = array(
                'SCHEMA_NAME'      => $this->foldCase($row[$nspname]),
                'TABLE_NAME'       => $this->foldCase($row[$relname]),
                'COLUMN_NAME'      => $this->foldCase($row[$colname]),
                'COLUMN_POSITION'  => $row[$attnum],
                'DATA_TYPE'        => $row[$type],
                'DEFAULT'          => $defaultValue,
                'NULLABLE'         => (bool) ($row[$notnull] != 't'),
                'LENGTH'           => $row[$length],
                'SCALE'            => null, // @todo
                'PRECISION'        => null, // @todo
                'UNSIGNED'         => null, // @todo
                'PRIMARY'          => $primary,
                'PRIMARY_POSITION' => $primaryPosition,
                'IDENTITY'         => $identity
			);
		}
		return $desc;
	}


	/**
	 * Adds an adapter-specific LIMIT clause to the SELECT statement.
	 *
	 * @param string $sql
	 * @param integer $count
	 * @param integer $offset OPTIONAL
	 * @return string
	 */
	public function limit($sql, $count, $offset = 0)
	{
		$count = intval($count);
		if ($count <= 0) {
			/**
			 * @see Zend_Db_Adapter_Exception
			 */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception("LIMIT argument count=$count is not valid");
		}

		$offset = intval($offset);
		if ($offset < 0) {
			/**
			 * @see Zend_Db_Adapter_Exception
			 */
			require_once 'Zend/Db/Adapter/Exception.php';
			throw new Zend_Db_Adapter_Exception("LIMIT argument offset=$offset is not valid");
		}

		$sql .= " LIMIT $count";
		if ($offset > 0) {
			$sql .= " OFFSET $offset";
		}

		return $sql;
	}

	/**
	 * Return the most recent value from the specified sequence in the database.
	 * This is supported only on RDBMS brands that support sequences
	 * (e.g. Oracle, PostgreSQL, DB2).  Other RDBMS brands return null.
	 *
	 * @param string $sequenceName
	 * @return string
	 */
	public function lastSequenceId($sequenceName)
	{
		$this->_connect();
		$value = $this->fetchOne("SELECT CURRVAL(".$this->quote($sequenceName).")");
		return $value;
	}

	/**
	 * Generate a new value from the specified sequence in the database, and return it.
	 * This is supported only on RDBMS brands that support sequences
	 * (e.g. Oracle, PostgreSQL, DB2).  Other RDBMS brands return null.
	 *
	 * @param string $sequenceName
	 * @return string
	 */
	public function nextSequenceId($sequenceName)
	{
		$this->_connect();
		$value = $this->fetchOne("SELECT NEXTVAL(".$this->quote($sequenceName).")");
		return $value;
	}

	/**
	 * Gets the last ID generated automatically by an IDENTITY/AUTOINCREMENT column.
	 *
	 * As a convention, on RDBMS brands that support sequences
	 * (e.g. Oracle, PostgreSQL, DB2), this method forms the name of a sequence
	 * from the arguments and returns the last id generated by that sequence.
	 * On RDBMS brands that support IDENTITY/AUTOINCREMENT columns, this method
	 * returns the last value generated for such a column, and the table name
	 * argument is disregarded.
	 *
	 * @param string $tableName   OPTIONAL Name of table.
	 * @param string $primaryKey  OPTIONAL Name of primary key column.
	 * @return string
	 */
	public function lastInsertId($tableName = null, $primaryKey = null)
	{
		if ($tableName !== null) {
			$sequenceName = $tableName;
			if ($primaryKey) {
				$sequenceName .= "_$primaryKey";
			}
			$sequenceName .= '_seq';
			return $this->lastSequenceId($sequenceName);
		}
		return $this->_connection->lastInsertId($tableName);
	}

}
